This application note provides a set of checklists that consist
of design guidelines, recommendations, and factors to consider when you create designs
MAX® 10 FPGAs.
Use this document to help you plan the FPGA and system early in the design process, which is crucial for a successful design.
Follow Intel’s recommendations throughout the design process to achieve good results, avoid common issues, and improve your design productivity.
MAX® 10Design Flow
Before You Begin
Before you begin planning and designing your
FPGA system, familiarize yourself with the FPGA device features, and the design
tools and IP that are available for the
Read through the Device Overview of the FPGA
The Device Overview provides an overview of the capabilities and options available for a device family. Read through the document to familiarize yourself with the device family offerings and general features.
Ensure your board design supports the OpenCore Plus tethered mode
You can program your FPGA and verify your design in hardware before you purchase an IP license by using the OpenCore Plus feature available for many IP cores. OpenCore Plus supports the following modes:
Untethered—your design runs for a limited time.
Tethered—your design runs for the duration of the
hardware evaluation period. This mode requires an Intel
FPGA download cable connected to the JTAG port on your board and a host computer that
Quartus® Prime Programmer. If you plan to use this mode, ensure
that your board design supports this mode.
Review available system development tools
Intel provides a complete suite of
development tools for every stage of your design.
Whether you are creating a complex FPGA
design as a hardware engineer, writing software for an embedded processor as a software
developer, modeling a digital signal processing (DSP) algorithm, or focusing on system
design, Intel has a tool that can help.
Estimate the required logic, memory, and multiplier density
MAX® 10 devices offer a range of densities
that provide different amounts of device logic resources. Determining the required logic
density can be a challenging part of the design planning process. Devices with more logic
resources can implement larger and potentially more complex designs but generally have a
higher cost. Smaller devices have lower static power utilization.
Consider vertical device migration availability and requirements
Determine whether you want the flexibility of migrating your design to another device density. Choose your device density and package to accommodate any possible future device migration to allow flexibility when the design nears completion.
To verify the pin migration compatibility, use the Pin Migration View window in the
Quartus® Prime software Pin Planner. The Pin
Migration View window helps you identify the difference in pins that can
exist between migration devices:
If one device has pins for connection to VCC or GND but are I/O pins on a different device,
Quartus® Prime software ensures these pins are not used for I/O. For
migration, ensure that these pins are connected to the correct PCB plane.
If you are migrating between two devices in the same
package, connect the pins that are not connected to the smaller die to VCC or GND on the larger die in your original
Review resource utilization reports of similar designs
If you have other designs that target an Intel device, you can
use their resource utilization as an estimate for your new design. Coding style, device
architecture, and optimization options used in the
Quartus® Prime software can
significantly affect resource utilization and timing performance of a design.
To estimate resource utilization for certain configurations of Intel's FPGA IP designs, refer to the respective
MAX® 10 user guides.
Reserve device resources for future development and debugging
Select a device that meets your design
requirements with some safety margin in case you want to add more logic later in the design
cycle, upgrade, or expand your design. You may also want additional space in the device to
ease design floorplan creation for an incremental or team-based
Determine the required number of I/O pins for your
application, considering the design’s interface requirements with other system
blocks. You can compile any existing designs in the
Quartus® Prime software to determine how
many I/O pins are used.
Other factors can also affect the number of I/O pins
required for a design, including simultaneous switching noise (SSN) concerns, pin
placement guidelines, pins used as dedicated inputs, I/O standard availability for each
I/O bank, differences between I/O standards and speed for row and column I/O banks, and
package migration options.
Consider the I/O pins you need to reserve for debugging
Intel provides a complete design
debugging environment that easily adapts to your specific design requirements. When
planning to debugging, you should decide which I/O pins you need to reserve for
Verify that the number of LVDS channels are enough
Larger densities and package pin counts offer more full-duplex LVDS channels for differential signaling. Ensure that your device density-package combination includes enough LVDS channels.
Verify the number of PLLs and clock routing resources
Verify that your chosen device density package
combination includes enough PLLs and clock routing resources for your design. GCLK
resources are shared between certain PLLs, which can affect the inputs that are available
The device speed grade affects the device timing performance and timing closure, as well as power utilization. One way to determine which speed grade your design requires is to consider the supported clock rates for specific I/O interfaces.
You can use the fastest speed grade while prototyping to reduce compilation time because less time is spent optimizing the design to meet timing requirements. If the design meets the timing requirements, you can then move to a slower speed grade for production to reduce cost.
When migrating to a device of different speed grade, check the timing
report from the timing analysis to ensure that there is no timing violation between
different blocks within the
MAX® 10 device, between
MAX® 10 devices and other devices on the board.
Always design with a sufficient timing margin so that your design can work on devices of different speed grades.
Determine the number of images supported for the device
Select a device that support dual configuration images, two
FPGA bitstreams, if dual configuration feature is needed in your design. All
MAX® 10 devices support the dual configuration feature, except 10M02
Early Board Design
Early planning allows the FPGA team to provide early information to PCB board and system designers.
Select a configuration scheme
Intel offers a wide range of configuration solutions to configure
MAX® 10 devices.
Data decompression—if you enable data compression, the storage requirement and the programming time (writing to flash) are reduced. The configuration time (writing to CRAM) is increased.
Design security—this feature utilizes a 128-bit security key to protect the designs from unauthorized copying, reverse engineering, and tampering. The devices can decrypt configuration bitstreams using the AES algorithm. Design security is not available for the JTAG configuration scheme.
Dual configuration—this feature is supported only in self-download mode.
SEU mitigation—dedicated circuitry in the devices
perform cyclic redundancy check (CRC) error detection and check for SEU errors
automatically. To detect SEU errors, use the CRC_ERROR pin to flag errors and design your system to take appropriate
action. If you do not enable the CRC error detection feature, you can also use the
CRC_ERROR pin as a design I/O pin.
Plan for the Auto-restart after configuration error option
To reset the device internally by driving the nSTATUS pin low when a configuration error occurs,
enable the Auto-restart after configuration
error option. The device releases its nSTATUS pin after the reset time-out period. This behavior allows you to
re-initiate the configuration cycle. The nSTATUS
pin requires an external 10-kΩ
pull-up resistor to VCCIO.
Estimating configuration file size
To estimate the configuration file size, convert your configuration file in uncompressed Raw Binary File (.rbf). The .rbf file size provides the approximate uncompressed configuration file sizes.
Use uncompressed .rbf size only to estimate the file size before design compilation. Different configuration file formats, such as Hexadecimal (Intel-Format) File (.hex) or Tabular Text File (.ttf) format, have different file sizes.
Take advantage of on-chip debugging features to
analyze internal signals and perform advanced debugging techniques.
Different debugging tools work better for different
systems and different designers. Early planning can reduce the time spent debugging, and
eliminates design changes later to accommodate your preferred debugging methodologies.
Adding debug pins may not be enough, because of internal signal and I/O pin
accessibility on the device.
Consider the guidelines to plan for debugging tools
Select on-chip debugging schemes early to plan memory and logic requirements, I/O pin connections, and board connections.
If you want to use Signal Probe incremental routing, the Signal Tap II Embedded Logic Analyzer, Logic Analyzer Interface, In-System Memory Content Editor, In-System Sources and Probes, or Virtual JTAG IP core, plan your system and board with JTAG connections that are available for debugging.
Plan for the small amount of additional logic resources used to implement the JTAG hub logic for JTAG debugging features.
For debugging with the Signal Tap II
Embedded Logic Analyzer, reserve device memory resources to capture data during
Reserve I/O pins for debugging with SignalProbe or the Logic Analyzer Interface so that you do not have to change the design or board to accommodate debugging signals later.
Ensure the board supports a debugging mode where debugging signals do not affect system operation.
Incorporate a pin header or micro connector as required for an external logic analyzer or mixed signal oscilloscope.
To use debug tools incrementally and reduce compilation time, ensure incremental compilation is on so you do not have to recompile the design to modify the debug tool.
To use the Virtual JTAG IP core for custom debugging applications, instantiate it in the HDL code as part of the design process.
To use the In-System Sources and Probes feature, instantiate the IP core in the HDL code.
To use the In-System Memory Content Editor for RAM or ROM
blocks or the LPM_CONSTANT IP core, turn on the Allow In-System Memory Content Editor option to capture and update
content independently of the system clock option for the memory block in the
Use the PowerPlay Early Power Estimator (EPE) to estimate power supplies and cooling solution
FPGA power consumption depends on logic design and is challenging to estimate during early board specification and layout. However, it is an important design consideration and must be estimated accurately to develop an appropriate power budget to design the power supplies, voltage regulators, decoupling capacitors, heat sink, and cooling system.
PowerPlay® EPE spreadsheet to estimate
power, current, and device junction temperature before you have a complete design. The
EPE calculates the estimated information based on device information, planned device
resources, operating frequency, toggle rates, ambient temperature, heat sinks
information, air flow, board thermal model, and other environmental considerations.
If you have an existing or partially-completed and compiled design—use the Generate PowerPlay Early Power Estimator File command in the
Quartus® Prime software to provide input to the EPE spreadsheet.
If you do not have an existing design—estimate
manually the number of device resources used in your design and input into the EPE
spreadsheet. If the device resources information changes during or after the design
phase, your power estimation results will be less accurate.
MAX® 10 devices require various voltage supplies depending on your design requirements. Use the following checklist to design the board for the FPGA power pin connections.
Design the board for power-up
MAX® 10 devices support hot socketing (hot
plug-in/hot swap) and power sequencing without the use of external devices. Consider the
During power-up, the output buffers are tri-stated and the internal weak pull-up resistors are disabled by default. You can enable the internal weak pull-up resistors through the
Quartus® Prime software.
with weak pull-up resistors enabled until the device is configured and configuration pins drive out.
Design the voltage power supply ramps to be monotonic—ensure that the minimum current requirement for the power-on-reset (POR) supplies is available during device power up. The following are the POR monitored power supplies:
VCC or VCC_ONE (after regulated down)
VCCIO of bank 1B and bank 8
Set the POR delay in the
Quartus® Prime software to ensure power supplies are stable. You can extend the POR delay by using an external component to assert the nSTATUS pin low. To ensure the device configures properly and enters user mode, extend the POR delay if the board cannot meet the maximum power ramp time specifications.
Design power sequencing and voltage regulators for the best device reliability—although power sequencing is not required for correct operation, consider the power-up timing of each rail to prevent problems with long-term device reliability if you are designing a multi-rail powered system.
Take advantage of the power up sequence for instant-on feature. With instant-on, the device can directly enter user mode with the shortest time after power supplies reach the required level. During power up, the control block reads the POR delay value and instant-on setting bits. If the instant-on is set, the device directly enters the initialization phase. If the instant-on feature is not selected, the POR delay value delays the POR signal. Clear the DSM if you want to change the setting.
Connect the GND between boards before connecting the power
supplies—Intel uses GND as a reference for hot-socketing operations and I/O
buffer designs. Connecting the GND between boards before connecting the power
supplies prevents the GND on your board from being pulled up inadvertently by a path
to power through other components on your board. A pulled up GND could otherwise
cause an out-of-specification I/O voltage or current condition with the device.
Explore unique requirements for FPGA power pins or other power pins on your board, and determine which devices on your board can share a power rail. It is especially important for you to consider the power supply sharing ability of devices from different device families.
Follow the suggested power supply sharing and isolation
guidance, and the specific guidelines for each pin.
Use power distribution network (PDN) tool to plan for power distribution and decoupling capacitor selection
MAX® 10 devices include on-die decoupling
capacitors to provide high-frequency decoupling.
To plan power distribution and return currents from the
voltage regulating module to the FPGA power supplies, you can use the PDN design tool
that optimizes the board-level PDN graphically. Although you can use SPICE simulation to
simulate the circuit, the PDN design tool provides a fast, accurate, and interactive way
to determine the right number of decoupling capacitors for optimal cost and performance
Depending on your configuration scheme, different pull-up or pull-down resistor, signal integrity, and specific pin requirements apply. Connecting the configuration pins correctly is important. Use the following checklist to address common issues.
Verify configuration pin connections and pull-up or pull-down resistors are correct for your configuration schemes
Intel provides pin connection guidelines to help you plan your design These guidelines describe each pin and give guidelines for their use.
Design configuration TCK pin using the same technique as in designing high-speed signal or system clock
Noise on the TCK signal can affect JTAG configuration.
For a chain of devices, noise on the TCK pin in the chain can cause JTAG programming or configuration to fail for the entire chain.
For a chain of devices, ensure all devices in the JTAG chain are powered on during JTAG programming or configuration.
Verify the JTAG pins are connected to a stable voltage level if not in use
JTAG configuration takes precedence over all
configuration methods. If you do not use the JTAG interface, do not leave the JTAG pins
floating or toggling during configuration.
To disable the JTAG circuitry, connect TCK pin to GND through a 1-kΩ resistor.
Connect TMS and TDI pins to VCCIO through a 1-kΩ resistor. Leave TDO unconnected.
Verify the JTAG pin connections to the download cable header
A device operating in JTAG mode uses the required TDI, TDO,
TMS, and TCK pins. The TCK pin does not
support internal weak pull-down.
Connect the TCK pin to an external 1-kΩ to 10-kΩ pull-down resistor. The
TDI and TMS pins have weak internal pull-up resistors. The JTAG output pin (TDO) and all JTAG input pins are powered by VCCIO. The voltage range is 1.5 V to 3.3 V.
The download cable must be powered at 2.5 V when VCCIO of the JTAG pins are powered at 2.5 V to 3.3 V
to prevent voltage overshoot because JTAG pins do not have internal PCI clamping diodes.
The TCK pin must be pulled to ground. If the
VCCIO of the JTAG pins are powered at 1.5 V or
1.8 V, the download cable should be powered by the same VCCIO.
Review the following JTAG pin connections guidelines:
If you have multiple devices in the chain, connect the
TDO pin of a device to the TDI pin of the next device in the chain.
Noise on the JTAG pins during configuration, user mode, or
power-up can cause the device to go into an undefined state or mode.
To disable the JTAG state machine during power-up, pull
the TCK pin low through a 1-kΩ
resistor to ensure that an unexpected rising edge does not occur on TCK.
Pull TMS and
TDI high through a 1-kΩ to
Ensure the download cable and JTAG pin voltages are compatible
The download cable interfaces with the JTAG pins of your device. The operating voltage supplied to the Intel FPGA download cable by the target board through the 10-pin header determines the operating voltage level of the download cable. The JTAG pins are powered by VCCIO.
In a JTAG chain containing devices with different VCCIO levels, the devices with a higher VCCIO level should drive the devices with the same or lower VCCIO level. A one-level shifter is required at the end of the chain with this device arrangement. If this arrangement is not possible, you have to add more level shifters into the chain.
Ensure all devices in the chain are connected properly
If your device is in a configuration chain, ensure all devices in the chain are connected properly and powered on.
Determine if you need to turn on device-wide output enable
MAX® 10 device supports an optional chip-wide output enable that allows you to override all tri-states on the device I/Os. When the DEV_OE pin is driven low, all I/O pins are tri-stated; when this pin is driven high, all pins behave as programmed.
To use the chip-wide output enable feature:
Turn on Enable device-wide output enable (DEV_OE) under the General category of the Device and Pin Options dialog box in the
Quartus® Prime software before compiling your design
Ensure that the DEV_OE pin is driven to a valid logic level on your board
Do not leave the DEV_OE pin floating
General I/O Pin Connections
Use the following checklist to plan your general I/O pin connections and to improve signal integrity.
Specify the state of unused I/O pins
To reduce power dissipation, set clock pins and other unused I/O pins As inputs tri-stated. By default, the
Quartus® Prime software set the input pins tri-stated with weak pull-up resistor enabled.
To improve signal integrity, in the Reserve all unused pins option under the Unused Pins category of the Device and Pin Options dialog box of the
Quartus® Prime software, set the unused pins As output driving ground. This setting reduces inductance by creating a shorter return path and reduces noise on the neighboring I/Os. However, do not use this approach if it results in many via paths that causes congestion for signals under the device.
Carefully check the pin connections in the Pin-Out File (.pin) generated by the
Quartus® Prime software when you compile your design. The .pin file specifies how you should connect the device pins. I/O pins specified as GND can be left unconnected or connected to ground for improved noise immunity. Do not connect RESERVED pins.
Refer to the Board Design Resource Center
If your design has high-speed signals the board design has a major impact on the signal integrity in the system.
Refer to the Board Design Guideline Solution Center
Noise generated by SSN—when too many pins in close proximity change voltage levels at the same time—can reduce the noise margin and cause incorrect switching. For example, consider these board layout recommendations:
Break out large bus signals on board layers close to the device to reduce cross talk.
If possible, route traces orthogonally if two signal
layers are next to each other, and use a separation of two to three times the trace
Voltage-referenced I/O standards require both a VREF and a termination voltage (VTT). The reference voltage of the receiving device tracks the termination voltage of the transmitting device. Consider the following items:
Each voltage-referenced I/O standard requires a unique termination setup. For example, a proper resistive signal termination scheme is critical in SSTL-2 standards to produce a reliable DDR memory system with superior noise margin.
Although single-ended, non-voltage-referenced I/O standards do not require termination, impedance matching is necessary to reduce reflections and improve signal integrity.
Differential I/O standards typically require a termination
resistor between the two signals at the receiver. The termination resistor must match
the differential load impedance of the signal line.
MAX® 10 on-chip series termination provides the convenience of no external
components. You can also use external pull-up resistors to terminate the
voltage-referenced I/O standards such as SSTL and HSTL.
Perform full board routing simulation using IBIS models
To ensure that the I/O signaling meets receiver threshold levels on your board setup, perform full board routing simulation with third-party board-level simulation tools using an IBIS model.
To select the IBIS output in the Quartus Prime software, on the Assignments menu, click Settings. Navigate to the Board-Level page of the EDA Tool Settings category. Under the Board-level signal integrity analysis section, in the Format option, select IBIS.
Configure board trace models for Quartus Prime advanced timing analysis
For a system to operate properly, signal integrity and board routing propagation delays must be taken into consideration. If you use an FPGA with high-speed interfaces in your board design, analyze the board level timing as part of the I/O and board planning.
Differential I/Os at the top left corner are located in the low speed region.
To generate a more accurate I/O delays and extra reports to gain better insights into the signal behavior at the system level, turn on Enable Advanced I/O Timing under the TimeQuest Timing Analyzer category in the Settings dialog box of your
Quartus® Prime project. With this option turned on, the TimeQuest Timing Analyzer uses simulation results for the I/O buffer, package, and board trace model to generate the I/O delays.
You can use the advanced timing reports as a guide to make changes to the I/O assignments and board design to improve timing and signal integrity.
In many design environments, FPGA designers want to plan top-level FPGA I/O pins early so that board designers can start developing the PCB design and layout.
Verify pin locations early in the FPGA place-and-route software
The FPGA I/O capabilities and board layout guidelines influence pin locations and other types of assignments. Starting FPGA pin planning early improves the confidence in early board layouts, reduces the chance of error, and improves the overall time-to-market.
Use the Quartus Prime Pin Planner for I/O pin planning, assignments, and validation
Early in the design process, the system architect typically has information about the standard I/O interfaces (such as memory and bus interfaces), IP cores to be used in the design, and any other I/O-related assignments defined by system requirements.
You can use the
Quartus® Prime Pin Planner for I/O pin assignment planning, assignment, and validation:
Quartus® PrimeStart I/O Assignment Analysis command checks that pin locations and assignments are supported in the target FPGA architecture. Checks include reference voltage pin usage, pin location assignments, and mixing of I/O standards.
You can use I/O Assignment Analysis to validate I/O-related assignments that you make or modify throughout the design process.
The Create/Import IP core feature of the Pin Planner interfaces with the parameter editor, and enables you to create or import custom IP cores that use I/O interfaces.
Enter PLL and LVDS blocks. Then, use the Create Top-Level Design File command to generate a top-level design netlist file.
You can use the I/O analysis results to change pin
assignments or IP parameters and repeat the checking process until the I/O interface
meets your design requirements and passes the pin checks in the
After planning is complete, you can pass the
preliminary pin location information to PCB designers.
After the design is complete, you can use the reports
and messages generated by the
Quartus® Prime Fitter for the final sign-off of the
Quartus® Prime software uses physics-based rules to define the number of I/O pins allowed in a particular bank based on the I/O's drive strength. These rules are based on noise calculation to analyze accurately the impact of I/O placement on the ADC performance. If you use the ADC block in your design, Intel recommends that you follow the guidelines.
Determine if your system requires voltage-referenced signaling
Voltage-referenced signaling reduces the effects of simultaneous switching outputs (SSO) from pins changing voltage levels at the same time (for example, external memory interface data and address buses).
Voltage-referenced signaling provides an improved logic transition rate with a reduced voltage swing, and minimizes noise caused by reflection with a termination requirement.
Additional termination components are required for the
reference voltage source (VTT).
Determine if your system requires differential signaling
Differential signaling eliminates the interface performance barrier of single-ended and voltage-referenced signaling, with superior speed using an additional inverted closely-coupled data pair.
Differential signaling avoids the requirement for a clean reference voltage. This is possible because of lower swing voltage and noise immunity with a common mode noise rejection capability.
Considerations for this implementation include the requirements for a dedicated PLL to generate a sampling clock, and matched trace lengths to eliminate the phase difference between an inverted and non-inverted pair.
Allow the software to assign locations for the negative
pin in differential pin pairs. You only need to assign the positive pins.
Verify that all voltage-referenced signals in each I/O bank are intended to use the bank's VREF voltage (for devices that support VREF pins)
To accommodate voltage-referenced I/O standards, each I/O bank supports multiple VREF pins feeding a common VREF bus. Set the VREF pins to the correct voltage for the I/O standards in the bank.
Each I/O bank can only have a single VCCIO voltage level and a single VREF voltage level at a given time. If the VREF pins are not used as voltage references, the pins cannot be used as generic I/O pins and must be tied to the VCCIO of that same bank or GND.
An I/O bank, including single-ended or differential standards, can support voltage-referenced standards as long as all voltage-referenced standards use the same VREF setting.
For performance reasons, voltage-referenced input standards use their own VCCIO level as the power source. You can place voltage-referenced input signals in a bank with a VCCIO of 2.5 V or below.
Voltage-referenced bidirectional and output signals must drive out at the VCCIO voltage level of the I/O bank.
Check the I/O bank support for LVDS features
Different I/O banks include different support for LVDS signaling. Some banks have lower speed performance. Allocate the pins according to your data rate requirement.
Verify the usage of the VREF pins that are used as regular I/Os
VREF pins have higher pin capacitance that results in a different I/O timing:
Do not use these pins in a grouped interface such as a bus.
Do not use these pins for high edge rate signals such as clocks.
Test pin connections with boundary-scan test
A boundary-scan test allows you to test pin connections at board level without using physical test probes while the device is operating normally. To perform the boundary-scan test, you must have the boundary-scan description language (BSDL) file of the device.
Use the BSDL files from www.altera.com to perform boundary-scan test on pre-configured
MAX® 10 devices. For post-configured devices, you must modify the BSDL file according to the design.
Use the UNIPHY IP core for each memory interface, and follow connection guidelines
The self-calibrating UNIPHY IP core is optimized to take advantage of the
MAX® 10 structure. The UNIPHY IP core allows you to set external memory interface features and helps set up the physical interface (PHY) best suited for your system. When you use the Intel memory controller IP core functions, the UNIPHY IP core is instantiated automatically.
If you design multiple memory interfaces into the device using
Intel® FPGA IP, generate a unique interface for each instance to ensure good results instead of designing it once and instantiating it multiple times.
Use dedicated DQ/DQS pins and DQ groups for memory interfaces
The data strobe DQS and data DQ pin locations are
MAX® 10 devices. Before you design your device pin-out, refer to the memory
interface guidelines for details and important restrictions related to the connections for
these and other memory related signals.
Make dual-purpose pin settings and check for any restrictions when using these pins as regular I/O
You can use dual-purpose configuration pins as
general I/Os after device configuration is complete.
Select the desired setting for each of
the dual-purpose pins on the Dual-Purpose
Pins category of the Device and Pin
Options dialog box. Depending on the configuration scheme, these pins can be
reserved as regular I/O pins, as inputs that are tri-stated, as outputs that drive ground,
or as outputs that drive an unspecified signal.
For configuration pins that used as general purpose
I/Os, take note of the limitations of the pins when operating in user mode.
You can also use dedicated clock inputs, which drive the GCLK
networks, as general purpose input pins if they are not used as clock pins. If you use
the clock inputs as general inputs, the I/O registers use arithmetic logic module
(ALM)-based registers because the clock input pins do not include dedicated I/O
The device-wide reset and clear pins are
available as design I/Os if they are not enabled.
Review available device I/O features that can help I/O interfaces
Check the available I/O features and consider the following guidelines:
Programmable current strength—ensure that the output buffer current strength is sufficiently high, but does not cause excessive overshoot or undershoot that violates voltage threshold parameters for the I/O standard. Intel recommends performing an IBIS or SPICE simulations to determine the right current strength setting for your specific application.
Programmable slew rate—confirm that your interface meets its performance requirements if you use slower slew rates. Intel recommends performing IBIS or SPICE simulations to determine the right slew rate setting for your specific application.
Programmable input/output element (IOE) delays—helps read and time margins by minimizing the uncertainties between signals in the bus. For delay specifications, refer to the relevant device datasheet.
Open-drain output—if configured as an open-drain, the logic value of the output is either high-Z or 0. This feature is used in system-level control signals that can be asserted by multiple devices in the system. Typically, an external pull-up resistor is required to provide logic high.
Bus hold—If the bus-hold feature is enabled, you cannot use the programmable pull-up option. Disable the bus-hold feature if the I/O pin is configured for differential signals. For the specific sustaining current driven through this resistor and the overdrive current used to identify the next driven input and level for each VCCIO voltage, refer to the relevant device datasheet.
Programmable pull-up resistors—weakly holds the I/O to the VCCIO level when in user mode. This feature can be used with the open-drain output to eliminate the need for an external pull-up resistor. If the programmable pull-up option is enabled, you cannot use the bus-hold feature.
Programmable pre-emphasis—increases the amplitude
of the high frequency component of the output signal, and thus helps to compensate
for the frequency-dependent attenuation along the transmission line.
Consider OCT features to save board space and verify that the required termination scheme is supported for all pin locations
Driver-impedance matching provides the I/O driver with controlled output impedance that closely matches the impedance of the transmission line to significantly reduce reflections. OCT maintains signal quality, saves board space, and reduces external component costs.
OCT RS are supported in the same I/O bank for different I/O standards if they use the same VCCIO supply voltage
Each I/O in an I/O bank can be independently configured to support OCT RS or programmable current strength
You cannot configure both OCT RS and programmable current strength or slew rate
control for the same I/O buffer
The first stage in planning your clocking scheme is to determine your system clock requirements:
Understand your device’s available clock resources and correspondingly plan the design clocking scheme. Consider your requirements for timing performance, and how much logic is driven by a particular clock.
Based on your system requirements, define the required clock frequencies for your FPGA design and the input frequencies available to the FPGA. Use these specifications to determine your PLL scheme.
Quartus® Prime parameter editor to enter your settings in ALTPLL IP core, and check the results to verify whether particular features and input/output frequencies can be implemented in a particular PLL.
Use the device PLLs for clock management
Connect clock inputs to specific PLLs to drive specific low-skew routing networks. Analyze the global resource availability for each PLL and the PLL availability for each clock input pin. Use the following descriptions for the clock signals in your design:
The GCLK networks can drive throughout the entire device, serving as low-skew clock sources for device logic.
IOEs and internal logic can also drive GCLKs to create internally generated GCLKs and other high fan-out control signals; for example, synchronous or asynchronous clears and clock enables.
PLLs cannot be driven by internally-generated GCLKs. The input clock to the PLL must come from dedicated clock input pins or from another pin/PLL-fed GCLK.
Ensure that you select the correct PLL feedback compensation mode
MAX® 10 PLLs support four different clock feedback modes.
Check that the PLL offers the required number of clock outputs and use dedicated clock output pins
You can connect clock outputs to dedicated clock output pins or clock networks.
MAX® 10 PLL only allows one clock output per PLL block. If your device have 4 PLLs, there are 4 clock outputs from the PLLs.
Use the clock control block for clock selection and power-down
Every GCLK network has its own clock control block. The control block provides the following features that you can use to select different clock input signals or power-down clock networks to reduce power consumption without using any combinational logic in your design:
Clock source selection (with dynamic selection)
Clock power down (with static or dynamic clock enable or
MAX® 10 devices, the clkena signals are supported at the clock
network level instead of at the PLL output counter level. This allows you to gate
off the clock even when you are not using a PLL. You can also use the clkena signals to control the dedicated
external clocks from the PLLs.
Check on the pin connection guidelines for the ADC pins
Quartus® Prime software uses physics-based rules to define the number of I/O pins allowed in a particular bank based on the I/O's drive strength. These rules are based on noise calculation to analyze accurately the impact of I/O placement on the ADC performance. If you use the ADC block in your design, Intel recommends that you follow the guidelines.
In complex FPGA design development, design practices, coding styles, and IP core usage have an enormous impact on your device's timing performance, logic utilization, and system reliability. In addition, while planning and creating the design, plan for a hierarchical or team-based design to improve design productivity.
Use synchronous design practices
In a synchronous design, a clock signal triggers all events. When all of the registers’ timing requirements are met, a synchronous design behaves in a predictable and reliable manner for all process, voltage, and temperature (PVT) conditions. You can easily target synchronous designs to different device families or speed grades.
Consider the following recommendations to avoid clock signals problems:
Use dedicated clock pins and clock routing for best results—dedicated clock pins drive the clock network directly, ensuring lower skew than other I/O pins. Use the dedicated routing network to have a predictable delay with less skew for high fan-out signals. You can also use the clock pins and clock network to drive control signals like asynchronous reset.
For clock inversion, multiplication, and division use the device PLLs.
For clock multiplexing and gating, use the dedicated clock control block or PLL clock switchover feature instead of combinational logic.
If you must use internally generated clock signals, register the output of any combinational logic used as a clock signal to reduce glitches. For example, if you divide a clock using combinational logic, clock the final stage with the clock signal that was used to clock the divider circuit.
In multi-clock designs, ensure that signals crossing clock
domains are properly synchronized using the synchronizer, a handshake mechanism, or a
Instead of coding your own logic, save your design time by
using Intel FPGA IP cores—a library of parameterized modules and
device-specific IP cores. The IP cores are optimized for Intel
FPGA device architectures and can offer more efficient logic synthesis and device
To ensure that you set all ports and parameters correctly, use the
Quartus® Prime parameter editor to build or change IP cores parameters.
For detailed information about a specific IP core, refer to the respective MAX 10 user guides.
Review the information on dynamic reconfiguration feature
MAX® 10 devices support dynamic reconfiguration—dynamically change the PMA settings or protocols of a channel affecting data transfer on adjacent channels.
Consider the Intel's recommended coding styles to achieve optimal synthesis results
HDL coding styles can have a significant impact on the quality of results for programmable logic designs. For example, when designing memory and digital system processing (DSP) functions, understanding the device architecture helps you to take advantage of the dedicated logic block sizes and configurations.
You can use the HDL templates provided in the
Quartus® Prime software as examples for your reference. To access the templates, right click the editing area in the
Quartus® Prime text editor and click Insert Template.
For additional tool-specific guidelines, refer to the
documentation of your synthesis tool.
Enable the chip-wide reset to clear all registers if required
MAX® 10 devices support an optional chip-wide reset that enables you to override all clears on all device registers, including the registers of the memory blocks (but not the memory contents).
DEV_CLRn pin is driven low—all registers are cleared or reset to 0. The affected register behave as if they are preset to a high value when synthesis performs an optimization called NOT-gate-push back due to register control signals.
DEV_CLRn pin is driven high—all registers behave as programmed.
To enable chip-wide reset, before compiling your design, turn on Enable device-wide reset (DEV_CLRn) under the Options list of the General category in the Device and Pin Options dialog box of the Quartus Prime software.
Use device architecture-specific register control signals
MAX® 10 logic array block (LAB) contains dedicated logic for driving register control signals to its ALMs. It is important that the control signals use the dedicated control signals in the device architecture. In some cases, you may be required to limit the number of different control signals in your design.
If the clock signal is not available when reset is asserted, an asynchronous reset is typically used to reset the logic.
The recommended reset architecture allows the reset signal to be asserted asynchronously and deasserted synchronously.
The source of the reset signal is connected to the asynchronous port of the registers, which can be directly connected to global routing resources.
The synchronous deassertion allows all state machines and registers to start at the same time.
Synchronous deassertion avoids an asynchronous reset
signal from being released at, or near, the active clock edge of a flipflop that can
cause the output of the flipflop to go to a metastable unknown state.
Review the synthesis options available in your synthesis tool
If you force a particular power-up condition for your design, use the synthesis options available in your synthesis tool:
By default, the
Quartus® Prime software Integrated Synthesis turns on the Power-Up Don’t Care logic option that assumes your design does not depend on the power-up state of the device architecture. Other synthesis tools might use similar assumptions.
Designers typically use an explicit reset signal for the design that forces all registers into their appropriate values after reset but not necessarily at power-up. You can create your design with asynchronous reset that allows you to power up the design safely with the reset active, regardless of the power-up conditions of the device.
Some synthesis tools can also read the default or initial values for registered signals in your source code and implement the behavior in the device. For example, the
Quartus® Prime software Integrated Synthesis converts HDL default and initial values for registered signals into Power-Up Level settings. The synthesized behavior matches the power-up conditions of the HDL code during a functional simulation.
Registers in the device core always power up to a low (0)
logic level in the physical device architecture. If you specify a high power-up level
or a non-zero reset value (preset signal), synthesis tools typically use the clear
signals available on the registers and perform the NOT-gate push back optimization
technique. If you assign a high power-up level to a register that is reset low, or
assign a low power-up value to a register that is preset high, synthesis tools cannot
use the NOT-gate push back optimization technique and might ignore the power-up
Consider resources available for register power-up and control signals
To implement a reset and preset signal on the same register, synthesis tools emulate the controls with logic and latches that can be prone to glitches because of the different delays between the different paths to the register. In addition, the power-up value is undefined for these registers.
Consider Intel's recommendations for creating design partitions
Partitioning a design for an FPGA requires planning to ensure optimal results when the partitions are integrated and ensures that each partition is well placed, relative to other partitions in the device.
Follow Intel's recommendations for creating design partitions to improve the overall quality of results. For example, registering partition I/O boundaries keeps critical timing paths inside one partition that can be optimized independently. Plan your source code so that each design block is defined in a separate file. The software can automatically detect changes to each block separately.
Use hierarchy in your design to provide more flexibility when partitioning. Keep your design logic in the leaves of the hierarchy trees; that is, the top level of the hierarchy should have very little logic, and the lower-level design blocks contain the logic.
Perform timing budgeting and resource balancing between partitions
If your design is created in multiple projects, it is important that the system architect provide guidance to designers of lower-level blocks to ensure that each partition uses the appropriate device resources:
Because the designs are developed independently, each lower-level designer has no information about the overall design or how their partition connects with other partitions, which can lead to problems during system integration.
The top-level project information, including pin locations, physical constraints, and timing requirements, should be communicated to the designers of lower-level partitions before they start their design.
The system architect can plan design partitions at the top level and use the
Quartus® Prime software Generate Bottom-Up Design Partition Scripts option on the Project menu to automate the process of transferring top-level project information to lower-level modules.
Create a design floorplan for incremental compilation partitions
A design floorplan avoids conflicts between design partitions and ensure that each partition is well-placed relative to other partitions. When you create different location assignments for each partition, no location conflicts occur.
A design floorplan helps avoid situations in which the Fitter is directed to place or replace a portion of the design in an area of the device where most resources have already been claimed.
Floorplan assignments are recommended for timing-critical partitions in top-down flows. You can use the
Quartus® Prime Chip Planner to create a design floorplan using LogicLock region assignments for each design partition.
With a basic design framework for the top-level design, the floorplan editor enables you to view connections between regions, estimate physical timing delays on the chip, and move regions around the device floorplan.
After you compiled the full design, you can also view
logic placement and locate areas of routing congestion to improve the floorplan
Specify your synthesis tool and use correct supported version
Quartus® Prime software includes integrated synthesis that fully supports Verilog HDL, VHDL, Intel hardware description language (AHDL), and schematic design entry. You can also use industry-leading third-party EDA synthesis tools to synthesize your Verilog HDL or VHDL design, and then compile the resulting output netlist file in the
Quartus® Prime software:
Specify a third-party synthesis tool in the New Project Wizard or the EDA Tools Settings page of the Settings dialog box to use the correct Library Mapping File (.lmf) for your synthesis netlist.
Intel recommends that you use the most recent version of third-party synthesis tools because tool vendors are continuously adding new features, fixing tool issues, and enhancing performance for Intel devices.
Different synthesis tools can give different results. If you want to select the best-performing tool for your application, you can experiment by synthesizing typical designs for your application and coding style, and comparing the results.
Perform placement and routing in the
Quartus® Prime software to get accurate timing analysis and logic utilization results.
Your synthesis tool may offer the capability to create a
Quartus® Prime project and pass constraints such as the EDA tool setting, device
selection, and timing requirements that you specified in your synthesis project. You
can use this capability to save time when setting up your
Quartus® Prime project for
placement and routing.
Review resource utilization reports after compilation
After compilation in the
Quartus® Prime software, review the device resource utilization information:
Use the information to determine whether the future addition of extra logic or other design changes introduce fitting difficulties.
If your compilation results in a no-fit error, use the information to analyze fitting problems.
To determine resource usage, refer to the Flow Summary section of the Compilation Report for a percentage representing the total logic utilization, which includes an estimation of resources that cannot be used due to existing connections or logic usage.
For more detailed resource information, view the reports under Resource Section in the Fitter section of the Compilation Report. The Fitter Resource Usage Summary report breaks down the logic utilization information and indicates the number of fully and partially used ALMs, and provides other resource information including the number of bits in each type of memory block.
There are also reports that describe some of the optimizations that occurred during compilation. For example, if you use the
Quartus® Prime Integrated Synthesis, the reports under the Optimization Results folder in the Analysis & Synthesis section provide information that includes registers that were removed during synthesis. Use this report to estimate device resource utilization for a partial design to ensure that registers were not removed due to missing connections with other parts of the design.
Low logic utilization does not mean the lowest possible ALM utilization. A design that is reported to be close to 100% may still have space for extra logic. The Fitter uses ALUTs in different ALMs, even when the logic can be placed within one ALM, so that it can achieve the best timing and routability results. Logic might be spread throughout the device when achieving these results. As the device fills up, the Fitter automatically searches for logic that can be placed together in one ALM.
Review all Quartus Prime messages, especially warning or error messages
Each stage of the compilation flow generates messages, including informational notes, warnings, and critical warnings. Understand the significance of warning messages and make changes to the design or settings if required.
Quartus® Prime user interface, you can use the Message window tabs to look at only certain types of messages. You can suppress the messages if you have determined that your action is not required.
Use the incremental compilation feature to preserve logic in unchanged parts of your design, preserve timing performance, and reach timing closure more efficiently. You can speed up design iteration time by an average of 60% when making changes to the design with the incremental compilation feature.
Ensure parallel compilation is enabled
Quartus® Prime software can run some algorithms in parallel to take advantage of multiple processors and reduce compilation time when more than one processor is available to compile the design. Set the Parallel compilation option on the Compilation Process Settings page of the Settings dialog box, or change the default setting in the Options dialog box in the Processing page from the Tools menu.
Use the Compilation Time Advisor
The Compilation Time Advisor provides guidance in making settings that reduce your design compilation time. On the Tools menu, point to Advisors and click Compilation Time Advisor. Using some of these techniques to reduce compilation time can reduce the overall quality of results.
Use the guidelines in the following checklist for analyzing your design timing and optimizing your timing performance.
Ensure timing constraints are complete and accurate
In an FPGA design flow, accurate timing constraints allow timing-driven synthesis software and place-and-route software to obtain optimal results. Timing constraints are critical to ensure designs meet their timing requirements, which represent actual design requirements that must be met for the device to operate correctly.
Quartus® Prime software optimizes and analyzes your design using different timing models for each device speed grade, so you must perform timing analysis for the correct speed grade. The final programmed device might not operate as expected if the timing paths are not fully constrained, analyzed, and verified to meet requirements.
Review the TimeQuest Timing Analyzer reports after compilation
Quartus® Prime software includes the
Quartus® Prime TimeQuest Timing Analyzer, a powerful ASIC-style timing analysis tool that validates the timing performance of all logic in your design. It supports the industry standard Synopsys Design Constraints (SDC) format timing constraints, and has an easy-to-use GUI with interactive timing reports. It is ideal for constraining high-speed source-synchronous interfaces and clock multiplexing design structures.
The software also supports static timing analysis in the industry-standard Synopsys Primetime software. To generate the required timing netlist, specify the tool in the New Project Wizard or the EDA Tools Settings page of the Settings dialog box.
Ensure that the I/O timings are not violated when data is provided to the FPGA
A comprehensive static timing analysis includes analysis of register to register, I/O, and asynchronous reset paths. It is important to specify the frequencies and relationships for all clocks in your design.
Use input and output delay constraints to specify external device or board timing parameters. Specify accurate timing requirements for external interfacing components to reflect the exact system intent.
The TimeQuest Timing Analyzer performs static timing analysis on the entire system, using data required times, data arrival times, and clock arrival times to verify circuit performance and detect possible timing violations. It determines the timing relationships that must be met for the design to correctly function. You can use the report_datasheet command to generate a datasheet report that summarizes the I/O timing characteristics of the entire design.
Perform Early Timing Estimation before running a full compilation
If the timing analysis reports that your design requirements were not met, you must make changes to your design or settings and recompile the design to achieve timing closure. If your compilation results in no-fit messages, you must make changes to get successful placement and routing.
You can use the Early Timing Estimation feature in the
Quartus® Prime software to estimate your design’s timing results before the software performs full placement and routing. On the Processing menu, point to Start and click Start Early Timing Estimate to generate initial compilation results after you have run analysis and synthesis.
Consider the following recommendations for timing optimization and analysis assignment:
Turn on Optimize
multi-corner timing on the Fitter Settings page in the Settings dialog
Use create_clock and create_generated_clock to specify the frequencies and relationships for
all clocks in your design.
Use set_input_delay and set_output_delay to specify the external device or board timing
Use derive_pll_clocks to create generated clocks for all PLL outputs,
according to the settings in the PLL IP cores. Specify multicycle relationships for
LVDS transmitters or receiver deserialization factors.
Use derive_clock_uncertainty to automatically apply inter-clock,
intra-clock, and I/O interface uncertainties.
Use check_timing to generate a report on any problem with the design or
applied constraints, including missing constraints
Quartus® Prime optimization features to achieve
timing closure or improve the resource utilization.
Use the Timing and Area Optimization Advisors to suggest
Perform functional simulation at the beginning of your design flow
Perform the simulation to check the design functionality or logical behavior of each design block. You do not have to fully compile your design; you can generate a functional simulation netlist that does not contain timing information.
Perform timing simulation to ensure your design works in targeted device
Timing simulation uses the timing netlist generated by the TimeQuest Timing Analyzer, which includes the delay of different device blocks and placement and routing information. You can perform timing simulation for the top-level design at the end of your design flow to ensure that your design works in the targeted device.
Specify your simulation tool and use correct supported version
Intel provides the
ModelSim* - Intel FPGA
Edition simulator Starter Edition and offers the
ModelSim* - Intel FPGA
Edition that enable you to take
advantage of advanced testbench capabilities and other features.
In addition, the
Quartus® Prime EDA Netlist Writer can generate timing netlist files to support other third-party simulation tools such as Synopsys VCS, Cadence NC-Sim, and Aldec Active-HDL.
If you use a third-party simulation tool, use the software version that is supported with your
Quartus® Prime software version.
Specify your simulation tool in the EDA Tools Settings page of the Settings dialog box to generate the appropriate output simulation netlist. The software can also generate scripts to help you setup libraries in your tool with NativeLink integration.
Use only the model libraries provided with your
Quartus® Prime software version. Libraries may change between versions and this can cause a mismatch with your simulation netlist.
To create a testbench in the
Quartus® Prime software, on
the Processing menu, point to
Start and click Start Testbench Template Writer.
Use the following guidelines if your design requires formal verification.
Determine if you require formal verification for your design
If formal verification is required for your design, it is easier to plan for limitations and restrictions in the beginning than to make changes later in the design flow.
Check for support and design limitations for formal verification
Quartus® Prime software supports some formal verification flows. Using a formal verification flow can impact performance results because it requires that certain logic optimizations be turned off, such as register retiming, and forces hierarchy blocks to be preserved, which can restrict optimization.
After compiling your design, analyze the power consumption and heat dissipation with the
PowerPlay® Power Analyzer to calculate the dynamic, static, and I/O thermal power consumption and ensure the design has not violated power supply and thermal budgets.
Power optimization in the
Quartus® Prime software depends on accurate power analysis results. Use the following guidelines to ensure the software optimizes the power utilization correctly for the design’s operating behavior and conditions.
Provide accurate typical signal activities to get accurate power analysis result
You need to provide accurate typical signal activities to PowerPlay Power Analyzer:
Compile a design to derive the information about design resources, placement and routing, and I/O standards.
Derive signal activity data (toggle rates and static probabilities) from simulation results or a user-defined default toggle rate and vectorless estimation. The signal activities used for analysis must be representative of the actual operating behavior.
For the most accurate power estimation, use gate-level simulation results with a Value Change Dump File (.vcd) output file from a third-party simulation tool. The simulation activity should include typical input vectors over a realistic time period and not the corner cases often used during functional verification. Use the recommended simulator settings, such as glitch filtering, to ensure good results.
Specify the correct operating conditions for power analysis
Specify the operating conditions, including the core voltage, device power characteristics, ambient and junction temperature, cooling solution, and the board thermal model.
Quartus® Prime software, select the appropriate settings on the Operating Settings and Conditions page in the Settings dialog box.
Analyze power consumption and heat dissipation in the PowerPlay Power Analyzer
Quartus® Prime software, on the Processing menu, click PowerPlay Power Analyzer Tool. The tool also provides a summary of the signal activities used for analysis and a confidence metric that reflects the overall quality of the data sources for signal activities.
PowerPlay® Power Analyzer report is a power estimate and is not a power specification. Always refer to the device datasheet for the power specification.
If your design includes many critical timing paths that require the high-performance mode, you might be able to reduce power consumption by using a faster speed grade device if available. With a faster device, the software might be able to set more device tiles to use the low-power mode.
Optimize the clock power management
Clocks represent a significant portion of dynamic power consumption, because of their high switching activity and long paths. The
Quartus® Prime software automatically optimizes clock routing power by enabling only the portions of a clock network that are required to feed downstream registers.
You can also use clock control blocks to dynamically enable or disable the clock network. When a clock network is powered down, all the logic fed by that clock network does not toggle, thereby reducing the overall power consumption of the device.
To reduce LAB-wide clock power consumption without disabling the entire clock tree, use the LAB-wide clock enable signal to gate the LAB wide clock. The
Quartus® Prime software automatically promotes register-level clock enable signals to the LAB level.
Reduce the number of memory clocking events to reduce memory power consumption. You can use clock gating or the clock enable signals in the memory ports.
Consider I/O power guidelines
The dynamic power consumed in the I/O buffer is proportional to the total load capacitance—lower capacitance reduces power consumption.
Dynamic power is proportional to the square of the voltage. Use lower voltage I/O standards to reduce dynamic power. Non-terminated I/O standards such as LVTTL and LVCMOS have a rail-to-rail output swing equal to the VCCIO supply voltage and consume little static power.
Dynamic power is proportional to the output transition frequency. Use resistively-terminated I/O standards such as SSTL for high-frequency applications. The output load voltage swings by an amount smaller than the VCCIO around a bias point. Because of this, the dynamic power is lower than for non-terminated I/O under similar conditions.
Resistively-terminated I/O standards dissipate significant static power because current is constantly driven into the termination network. Use the lowest drive strength that meets your speed and waveform requirements to minimize static power when using resistively terminated I/O standards.
The power used by external devices is not included in the PowerPlay Power Analyzer calculations. Ensure that you include the external devices power separately in your system power calculations.
Reduce design glitches through pipelining and retiming
A design that has many glitches consumes more power because of faster switching activity. Pipelining by inserting flip flops into long combinational paths can reduce design glitches.
However, if there are not many glitches in your design, pipelining may increase power consumption due to the addition of unnecessary registers.
Review the information on power-driven compilation and Power Optimization Advisor
Quartus® Prime software offers power-driven compilation to fully optimize device power consumption. Power-driven compilation focuses on reducing your design’s total power consumption using power-driven synthesis and power-driven place-and-route.
Reduce power consumption with architectural optimization
Use specific device architecture features to reduce power consumption.
For example, use the dedicated DSP block available in the MAX 10 device in place of LEs to perform arithmetic-related functions; build large shift registers from RAM-based FIFO buffers instead of building the shift registers from the LE registers.